Pin-and-box joint for stone-dri lls



UNITED STATES ATENT Fries.

PlN-AND-BOX JOINT FOR STONE-DRILLS.

SPECIFIOATION forming part of Letters Patent No. 295,347, dated March 18, 1884.

Application filed August 3, 1883. (No model.)

'50 mil whom it may concern: 4

Be it known that I, DUNCAN CAMERON, a citizen of Ontario, Canadmresiding at Bandolph, in the county of Oattaraugus and State of New York, have invented certain new and useful Improvements in Pin-and-Box Joint Stone-Drills; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the construction of toois for drilling oil or other deepbored wells; and it consists in improvements on thescrew- 1 joint by which the drill or other tool is attaohed to the drill-stock, which joint is commonlycalled the pin and box. It is at thist point that the tool almost alwaysbreaks while in use, and many forms have been devised to add strength there withoutincreasing the size. One form employed for this purpose consisted in making the pin and box'with two separate screws of equal pitch but unequal diameter, or, in other words, making an inner pin and box.

The present invention consists in improvements upon the said construction. The difli culty found with the said construction was that in practice it was found impossible to make both screws seat, owing to difference of expan sion and contraction from changes in temperature, and in keeping their seats free from dirt, it being difficult to get at the inner seat to keep it clean, and if not perfectly clean the outer seat would not abut. For the above reasons the construction named has never come into general use.

My invention is shown in the accompanying drawing by a single figure, which is an elevation of the pin and a vertical section of the box.

A is the box, and has two female screws, 0; a, of equal pitch but unequal diameters.

B B is the pin, and is formed of two screws to connect with the two screws in the box, being in effect a double or a shouldered pin. Between the two pins is a curved or braced shoulder, 21, and at the base of the main pin is a second shoulder, b. These latter add greatly to the strength of the pins. It will be observed that the shoulder 11 has no seat, and that the only seat for the whole joint is at s. This is the essential feature of the construetion, as it effectually overcomes the difficulties above named, and thus secures all the benefits sought to be obtained by the construction. The curved or beveled shoulders b and b are of great value, and especially the one at b. The one at b may be omitted, if desired. The shoulder between the female screws cand a. may be beveled also, but there should be no seat at that point.

What I claim as new is- 1. In a pin-andboxjoint for well-drills, the combination, with the box A, having the two female screws a c, of the pin B B, with beveled shoulders 22,-said parts having a single seat, 8, as set forth.

2. In a pin-and-box joint for well-drills, a pin consisting of the parts B B and beveled shoulders I) b, in combination with a box, A, constructed, as shown, to receive said pin, with asingle seat, 8, for the purposes mentioned.

In testimony whereof I affix my signature in presence of two witnesses.

DUN CAN CAMERON.

Witnesses:

GEO. A. STURGEQN, W. E. PIOKERING. 

